N-Unsubstituted 2-thiophenemethanimine and 3-thiophenemethanimine are the simplest derivatives of a family of imines, the thienyl imines. These two thienyl aldimines and the C-methyl derivatives were prepared in a gas solid reaction by dehydrocyanation of the corresponding α-aminonitriles or in the gas phase by a retro-ene reaction from N-allyl derivatives, then characterized by IR and NMR spectroscopy at low temperature and used in transimination reactions. From several angles, these compounds in the free or complexed state have been compared to the corresponding recently synthesized furanimines and to other N-unsubstituted imines, with the aim of studying the specificity of each of them.